The LPG feeding system for an internal combustion engine usually involves the use of feeding devices including a LPG tank (part in liquid and part in gaseous phase), a group of reducer/vaporizer heated through the engine cooling liquid and two separate gas feeding systems both connected to the tank in different points to take one the gaseous LPG and the other the liquid LPG. The known feeding devices also include a selecting group to activate the gas circuit during the gas feeding (or LPG) gaseous phase when the engine cooling liquid temperature is lower than a determined value threshold and to activate the gas circuit feeding LPG in liquid phase as soon as the temperature of the cooling liquid exceed the above threshold value. In other words, the selecting group manages the switch from the gaseous to liquid feeding as soon as the cooling liquid is able to supply the necessary thermic energy for the vaporization of the liquid LPG.
The known feeding systems as described before, even if used, are complex under the manufacturing point of view especially for the two gas distinct feeding systems and the selecting group.